Exemplary embodiments of the invention relate to a method for producing a semiconductor body having a recombination zone, to a semiconductor component having a recombination zone, and to a method for producing such a semiconductor component.
Recombination is understood to mean the coming together again of electron-hole pairs. In silicon, recombinations generally proceed by way of recombination centers. These involve contaminations of the semiconductor material which represent a defect. From an energetic standpoint, these defects lie in the forbidden band.
For some rapidly switching applications it is desirable to realize a significantly reduced carrier lifetime in the semiconductor body, in particular in the drift zone in the case of power semiconductor components, such as, for example, an IGBT or a fast freewheeling diode. This makes it possible for example to reduce the reverse current and the turn-off losses.
Previously known possibilities for reducing the carrier lifetime in such semiconductor components consist in exposing the semiconductor components to an irradiation with high-energy particles, such as electrons, for example, which bring about damage to the crystal lattice and thus the production of recombination centers. Another possibility is the indiffusion of heavy metals, such as platinum or gold, for example, from the front side of the wafer.
In both variants, however, the front side, in particular a gate oxide situated thereon, is adversely influenced by the front-side irradiation or by the diffusion from the front side. Thus, by way of example, an undesirable shift in the threshold voltage or else an instability of the electrical properties can occur.